The invention to which this application relates is to improvements to a valve assembly and particularly, although not necessarily exclusively, to a valve assembly in the form of a block and bleed valve assembly in which there is provided first or first and second, or more, valve balls located along a fluid passage formed in the body of the valve.
Conventionally, the manufacture of the block and bleed valve, is well known however there is always pressure with regard to the design of the same to ensure that the dimensions of the valve, and in particular, the length of the same, meet International standards.
The applicant has a sense of granted patents and co pending patent applications which address this issue and further prior art documents are known such as, EP1322886, which also attempt to address the dimensional challenges, with varying degrees of success.
The applicant has identified that for certain requirements the prior art valve assemblies do not provide a satisfactory solution.
The aim of the present invention is therefore to provide a new form of valve assembly which allows the same to fulfill the requirements for International standards while, at the same time, take into account commercial and manufacturing considerations.
In a first aspect of the invention, there is provided a valve assembly, said valve assembly including at least one passage along which fluid can be selectively allowed to pass, said assembly including a valve body in which the passage is formed and at least one ball located in the passage so as to be moveable between a first position 1n which a channel in the ball forms part of the passage and a second position 1n which the ball prevents fluid passing along the passage and wherein at at least one end of the body and depending inwardly towards one side of the at least one ball there is provided a retention assembly, said assembly comprising a first annular member to contact with the ball, a second annular member receiving and locating at least one biasing means, said first and second annular members located within an annular housing, said annular housing retained within the valve body, and an annular securing member which is engaged with the valve body and which has an outer face which forms or receives an external sealing face for the valve assembly to a pipeline or pipeline flange.
In one embodiment the annular housing and annular securing member are independently retained with the valve body.
In an alternative embodiment the annular housing 1S retained 1n the valve body by the annular securing member.
Typically, the external sealing face, 1S adapted in a suitable manner so as to allow the same to be engaged and sealed with a pipeline or a pipeline flange in conjunction with which the valve is to be used.
In one embodiment, a retaining assembly as described is provided at each end of the valve body.
In one embodiment, the valve assembly includes at least first and second balls provided at spaced locations along the fluid passage formed in the valve body and a first retaining assembly is provided at the first end of the valve body to contact with one side of the first ball. In one embodiment a second retaining assembly is provided at the other end of the valve body to locate with a side of the second ball.
Typically, a sealing assembly is provided between the first and second balls so as to locate with the respective opposing sides of the balls which are not in contact with a retaining assembly.
In one embodiment there is provided a first annular seat for contact with a face of a first ball and a second annular seat for contact with a face of the second ball and said first and second seats are provided with at least one biasing means depending between the same.
In one embodiment a plurality of biasing means are provided spaced apart around a circular path at the periphery of the said passage.
In one embodiment the biasing means pass through a channel formed in a portion of the body or another member which depends partially inwardly so as to locate the biasing means with respect to the longitudinal axis of the same.
In one embodiment the first annular member is formed as a valve seat for sealing contact with the ball side. In this embodiment the valve seat and hence first annular member is formed of a metal or metal alloy. In an alternative embodiment the first annular member supports and receives thereon a valve seat. In this embodiment the valve seat is formed of a rubber or equivalent material.
In one embodiment, the biasing means provided in the second annular member are a series of springs provided at spaced locations around a circular path. In one embodiment first ends of the springs are located in the second annular member. In one embodiment the said spring ends are received and located in a part of the second annular member which is received in a recessed portion in the first annular member so as to locate the second annular member. In whichever embodiment the springs are provided within the retention assembly so that the same are held in compression so as to act on the first annular member to bias the first annular member towards contact with the ball.
In one embodiment, the opposing ends of the biasing means springs are located with the face of the annular housing which in turn is retained in position within the valve body by the threaded engagement of the annular securing member with the valve body. Thus, it can be ensured that at all times, the biasing means springs exert sufficient force on the first annular member so as to provide a sufficient seal with the ball.
Typically, sealing means are provided between the first annular member and the annular housing and the second annular member with the annular housing.
Typically, at least one sealing means is provided between the annular housing and the valve body.
Typically, at least one sealing means is provided between the annular ring and the valve body.
In a further embodiment of the invention, the biasing means are provided to act on the second annular member and are located within the annular housing such that the biasing means springs act on the second annular member to move the same towards the first annular member and in turn, to move the first annular member into engagement with the ball.
In one embodiment the components which are located within and along the valve body are moved into position from one, common, end of the valve body and the components are retained in position by the engagement of the annular housing and/or annular securing member in position at or adjacent to the end of the body from which the components are moved into position, once the components are in position.
In one embodiment the components include, In order of insertion into the valve body, a first sealing ring for a first valve ball, the first valve ball, a spigot for the first valve ball, a sealing assembly for the first valve ball and a second valve ball, the second valve ball, a spigot for the second valve ball, the annular housing with first and second sealing members located therein, and an annular securing member.
In a further aspect of the invention there is provided a retaining assembly for use in a valve assembly to retain the components of the valve passage therein, said retaining assembly including an annular housing having first and second annular members located therein and an annular securing means wherein one or both of the annular housing and/or annular securing means, are provided in engagement with the valve assembly body so as to retain the retaining assembly in position and provide the first and second annular members in the required position within the valve body.
Further aspects of the invention which can be used separately to, or in conjunction with, the valve assembly features described above, are now described.
In the further aspect of the invention, there is provided a valve assembly, said valve assembly including a valve body having a fluid passage therein and at least one ball mounted in the passage, said ball moveable between a first position in which a channel in the ball is provided in line with the passage so as to allow fluid to flow there through and a second, closed position in which the ball prevents fluid from passing along the passage, said ball mounted on first and second trunnions so as to be rotatable and wherein at least one of said trunnions is mounted and located internally of the valve body.
This is in contrast to the conventional fixed trunnion arrangement in which there is typically provided first and second trunnions locating with opposing sides of the ball and each of said trunnions is located to the exterior of the valve, one having a stem which can be operated to turn the valve ball and the other trunnion having a flange which is located externally of the valve body and which is bolted in position to secure it to the valve body.
Typically, the location of the flange and the bolting of the same on the valve body means that the valve body has to be of a relatively large size to receive the bolts and to provide the strength for securing the flange and hence lower trunnion to the valve body. This problem is overcome by the current invention in that the lower trunnion is located within a recess depending into the valve body from the fluid passage such that the lower trunnion does not have to pass through the valve body and does not have to be located externally of the valve body.
By locating the trunnion within the valve body, there is no need to bolt the same externally to the valve body and hence the dimensions of the valve body can be reduced significantly.
In one embodiment, the lower trunnion is formed as a solid cylinder or peg, with a first end received within the recess of the valve body and a second end received within a recess of the ball.
In one embodiment the said cylinder or peg is introduced into position within the valve body by first placing the ball into position in the valve body and then passing the peg or cylinder into the channel in the ball and then through a locating aperture in the ball and into the receiving recess of the valve body so that the peg or cylinder is received in the recess and the locating aperture.
In one embodiment a securing means is then put into position to secure the peg or cylinder in position with the ball and/or valve body.
Typically, the movement of the ball with respect to the peg and valve body is achieved by movement of the first trunnion opposing the said peg and which can be provided in a conventional manner.
Typically the second trunnion is located on the opposite side of the ball from the first trunnion and the longitudinal axes of the first and second trunnions define the axis of rotation of the ball between first and second positions.
In a further aspect of the invention there is provided a valve assembly including at least one passage along which fluid can be selectively allowed to pass, said assembly including a valve body in which the passage is formed and at least first and second balls located in the passage, each selectively movable between a first position in which a channel in the ball forms part of the passage and a second position in which the ball prevents fluid passing along the passage and wherein a sealing assembly is provided in the space in the valve body between said balls, said sealing assembly including a sealing ring for location with a face of a first ball and a sealing ring for location with a face of the other of said balls and wherein biasing means are provided with a first end of each of the biasing means located to act on the first sealing ring and a second end located to act on the second sealing ring.
In one embodiment the first and second sealing rings are separate components.
In one embodiment at any given time the biasing means act to bias one of the sealing rings into contact with the respective ball surface.
In one embodiment a plurality of biasing means are provided spaced along a circular path.
In one embodiment the biasing means are located in position by the location of the ends with the respective sealing rings.
Typically at least a portion of the biasing means intermediate the ends of the same are located in a channel for each respective biasing means. Preferably the said channels are formed in a portion of the valve body. The provision of the locating channels acts to prevent the possibility of the springs being twisted along their longitudinal axes by the rotational movement of the sealing rings which may occur during use of the valve. Typically the said portion protrudes into the passage of the valve body and IS located intermediate the first and second sealing rings.
In an alternative embodiment the said channels are provided In a member located between the first and second sealing rings.
In a yet further aspect of the invention there is provided a valve assembly including at least one passage along which fluid can be selectively allowed to pass, said assembly including a valve body in which the passage is formed and at least one ball located in the passage so as to be moveable between a first position in which a channel in the ball forms part of the passage and a second position in which the ball prevents fluid passing along the passage and at at least one end of the body and depending inwardly towards one side of the at least one ball there is provided a retention assembly and wherein the components to be located along the passage of the valve body are introduced into the valve body from the same common end and then retained in position by the movement of the said retention assembly into position at said end of the valve body.
In one embodiment the retention assembly is an annular securing member provided to be engaged with the valve body.
In one embodiment the retention assembly includes a first annular member to contact with the ball, a second annular member receiving and locating at least one biasing means, said first and second annular members located within an annular housing, said annular housing retained within the valve body, and the annular securing member which is engaged with the valve body and which has an outer face which forms or receives an external sealing face for the valve assembly to a pipeline or pipeline flange.
In one embodiment, for a single ball valve the components which are moved into position and located within the passage from the common end include a first sealing ring for a first ball, a first ball, a trunnion for the first ball a sealing assembly for sealing against the opposing surface of the first ball from the first sealing ring and the annular securing member.
In one embodiment, for a double ball valve the components located within the passage from the common end include a first sealing ring for a first ball, a first ball, a trunnion for locating the first ball, a sealing assembly for sealing against the opposing surface of the first ball from the first sealing ring, and a surface of a second ball, the second ball, a trunnion for locating the second ball, means for sealing against the opposing surface of the second ball from the sealing assembly and the annular securing member.
Typically the sealing assembly includes biasing means which are located in position by respective sealing rings for the first and second balls.
Typically the valve assembly formed is what is commonly referred to as a double block and bleed valve assembly.
In a yet further aspect of the invention there is provided a method of positioning and locating the components required within a body of a valve assembly to form the same, said valve assembly including first and second balls located along a passage within a valve body and along which passage fluid can be selectively allowed to flow by selectively positioning the said first and second balls by rotating the same, said method comprising the steps of introducing from one open end of the valve body and into the same so as to be positioned along said passage, a first sealing ring for a first ball, a first ball, a trunnion for locating the first ball, a sealing assembly for sealing against the opposing surface of the first ball from the first sealing ring, and a surface of a second ball, the second ball, a trunnion for locating the second ball, means for sealing against the opposing surface of the second ball from the sealing assembly and an annular securing member.
Typically at least the annular securing member is engaged with the valve body so as to close the passage at the open end to a sufficient extent to retain the components in position within the valve body.
Specific embodiments of the invention are now described with reference to the accompanying drawings; wherein